In an earlier application (Ser. No. 829,814), now U.S. Pat. No. 4,182,957, a process has been disclosed for determining the flow of fine grained or dust-like solid fuels into a gasifier such as is used in a partial oxidation process. The fuel in these cases is suspended in a gaseous or vaporous medium and is measured immediately prior to entry into the gasifier by means of a radiometric density measurement.
The earlier application related in particular to that case where the fuel was suspended in oxygen or air or an oxygen-enriched air and water vapor. The quantities found for the flow volume of the gaseous or vaporous reaction media and the quantity determined in the radiometric density measurement of the fuel flow relating to the total density of the flow were fed into a computer in which a signal indicating or controlling the volume flow for the fuel input was produced according to a specific mathematical relationship. In this process the flow volume of the fuel such as coal was considered negligible and was not utilized in the computer during the signal production process.
It has, however, now been found in actual use that this neglect was only justified if the gaseous or vaporous medium was loaded with the fine grained or dust-like fuel up to a limit of about 2 kg of fuel/m.sup.3 of gas. It has been found, on the other hand, that this amount is exceeded in many cases, such as where the gasifier is operated at an elevated pressure. The load amounts may then actually have a magnitude equal to or greater than 300 kg of fuel/m.sup.3 `of gas. In these cases it is no longer possible to disregard the flow volume of the fuel. This flow volume must then be considered in the computer calculations.
In addition, and contrary to the general embodiment described in the prior application, the fuel is frequently suspended in an inert carrier gas (preferably nitrogen), and not in the gaseous or vaporous reaction media constituted by oxygen or air and water vapor.
It is therefore an object of the present invention to provide for an improvement of the previously disclosed process which also takes into consideration the flow volume of the fuel in the input to the computer and where the fuel also may be suspended in an inert carrier gas, preferably nitrogen.